Recent research has suggested that the basal ganglia play an important role in the regulation of brain function and behavior in both adults and during early postnatal development. Behavioral disorders resulting from interference with basal ganglionic function include inability to initiate and perform complex patterns of movement and difficulties in performing complex cognitive tasks. To assess the bases of these deficits we are undertaking a research program which includes: electrophysiological studies of basal ganglionic neurons in intact animals and animals subjected to brain lesions, behavioral studies of disturbances produced by lesions involving the basal ganglia and studies of correlations of basal ganglionic neuronal activity with performance of specific behavioral tasks. These studies will provide important information concerning normal and abnormal functions of the basal ganglia and will hopefully suggest surgical or pharmacological treatments in alleviating deficits produced by basal ganglia disorders.